Find method Azure KeyPairService

Right now, the `find` method in `AzureKeyPairService` always returns a list with only one item, essentially duplicating `get` and wrapping it in a singleton list (name and id are the same property at the moment).
We could alternatively have it list all keypairs within a Resource Group & Storage Account, and do a non-exact match that would return a list with all matches (similar to the OpenStack implementation).